import math

(x1,y1,x2,y2) = map(float,raw_input().split())
print math.hypot(x2-x1,y2-y1) import math math (x1,y1,x2,y2) = map(float,raw_input().split()) (x1,y1,x2,y2) x1 y1 x2 y2 map(float,raw_input().split()) map float raw_input().split() ().split () raw_input split print math.hypot(x2-x1,y2-y1) math.hypot math hypot x2-x1 x2 x1 y2-y1 y2 y1
import math

(x1,y1,x2,y2) = map(float,raw_input().split())
print math.hypot(x2-x1,y2-y1)